The effect of storage on ice and various freezing treatments on enzyme leakage in muscle tissue of rainbow trout (Oncorhynchus mykiss)

Abstract

In order to study the biochemical changes in fish muscle during ice storage and freezing-thawing processes, the activities of certain marker enzymes in the cell interstitial fluid from muscle tissue of rainbow trout (Oncorhynchus mykiss) were measured. The enzymes analysed were: lysosomal alpha-glucosidase (E.C. 3.2.1.20), beta-N-glucosaminidase (E.C. 3.2.1.30) and acid phosphatase (E.C. 3.1.3.2). The activity in centrifuged tissue fluid (CTF) was compared with the activity in total homogenate. When ice storage was varied between 3 and 14 days, it did not affect enzyme leakage into the CTF significantly. However, there was a distinct difference between fresh fish and fish iced even for only 1 day, which gave increased leakage of marker enzymes. When the ice-stored samples were subject to a freezing-thawing cycle they showed a marked increase in enzyme activity in the press juice. When the freezing process was varied so as to achieve different freezing rates, the slowest freezing rate caused the highest enzyme leakage.

Frozen herring as raw material for spice-salting

“…Freezing and thawing of ®sh are known to cause rupture of cellular membranes, lysis of organelles such as mitochondria and lysosomes, and liberation of otherwise bound enzymes. 20,21 A rupture of the acinar cells in the intestine and pyloric caeca may cause leakage of proenzymes of the dominating intestinal proteases, such as trypsin and chymotrypsin, into the intestinal lumen. This may increase the activation rate of these enzymes during thawing.…”

Effect of freeze–thaw cycles on physicochemical properties and color stability of beef semimembranosus muscle

“…Factors affecting meat protein include ice crystal formation, dehydration, increased solute concentration, fat hydrolysis and or oxidation, atmospheric gasses (particularly oxygen), protein oxidation and proteolysis, and rigor temperature (Matsumoto, 1979;Shenouda, 1980). However, quality deterioration also occurs during freezing and frozen storage due to the osmotic removal of water, denaturation of protein and mechanical damage (Thyholt & Isaksson, 1997), and release of enzymes and other components from meat (Nilsson & Ekstrand, 1993). Thawing plays an important role in membrane disintegration as well as affecting sensory attributes (Nilsson & Ekstrand, 1994).…”

THE BIOCHEMICAL AND SENSORY PROPERTIES OF GILTHEAD SEA BREAM (SPARUS AURATA) FROZEN AT DIFFERENT CHARACTERISTIC FREEZING TIMES

“…The enzymes β ‐N‐acetyl‐glucosaminidase ( β ‐NAG) and α ‐glucosidase (AG) are not specifically associated with any particular subcellular organelle, but the activity of these enzymes under acid assay conditions is regarded as evidence of lysosomal activity, i.e., cell damage (Barrett and Heath 1977). The activities of β ‐NAG and AG in fluids obtained by centrifugation, i.e., “centrifugal tissue fluids (CTFs),” and the volume and protein content of the fluids have been found to correlate with the cellular damage caused by different freezing and thawing treatments in several fish species (Nilsson and Ekstrand 1993, 1994; Benjakul and Bauer 2000). Moreover, the activity of the mitochondrial enzyme β ‐hydroxy‐acyl‐coenzyme‐A dehydrogenase ( β ‐HADH) has been regarded as a measure of the damage caused in mitochondria by various freezing and thawing treatments of meat products (Gottesman and Hamm 1983).…”